DE2461168C2 - Measuring method and device for its implementation - Google Patents

Description

The connection relates to a measurement method to determine the relative position of an object and to a device for its implementation.

A certain number of devices are currently known for performing these measurements. all of which are based on the fact that a detuning is caused by a metallic mass that is brought into the vicinity of an oscillating circuit. The object, the position of which is to be measured, can either influence the value of an inductance or a capacitance which is located in an oscillating circuit of a measuring head. In these apparatus, however, it is necessary that the measuring head must be relatively close to the object whose position is to be measured. which can be a hindrance in certain cases. On the other hand, these measuring heads must have very good characteristics with regard to frequency if one wants to achieve great precision. In addition, with these devices one can only ctinmi'm the position of objects. whose material · - · property! · ¹ "are in a position to influence either an inductance value or a capacitance value or both at the same time. This means, however, that their use is limited

The German Auslegeschrift 12 22 6SH describes a device in which a generator inside a waveguide generates an electromagnetic or acoustic standing wave. The waveguide is completed by a short-circuit piston that is attached to the movable work table. while the waveguide on the stationary machine bed is appropriate. Two distant ventilating organs. which penetrate the Hohlleilerwancl, sample the amplitude of the standing wave. The ones from

Movement transmitted to the short-circuit piston causes a corresponding movement of the standing wave: somn .indem see the through the Scanning organs sampled amplitudes, indicating the movement allowed to evaluate

Since the Messohjekt is directly and mechanically connected to the MeIU οι direction, this Mcßvniriehuivj must be relatively close to the Mcßoh | ckl; m »Ehraehi m. In: on the other hand, this Messohjeki can only perform one type of movement, namely only dieicnue. that you want to lens In the case of the extension l2 22hKX, the workbench may only make a to and fro, straight-line movement: so. ./ \ AuIViilem. since the measurement of the value is traced back to an amplitude measurement. the measuring accuracy wedge is very relative.

Is it! the aim of the present application. to avoid these disadvantages associated with the known devices and to specify a tube and a device for determining the relative position of any object. D ¹ CSeS target is achieved with a measuring method, which is characterized in that the distance between an antenna and a target is used as a resonator of a hyperfrequency oscillator, the frequency of which with a reference frequency. which corresponds to that of said oscillator for a predetermined distance antenna target, is compared, the result of the comparison being a measure of the difference between the valley distance antenna target and the predetermined distance.

The device for carrying out the method is characterized in that a first Hyperfrequency oscillator with at least one short-band A microwave generator, an antenna and a feedback circuit supplies a wave whose Frequency depends on the distance antenna target that a / further hyperrequency oscillator with a semi-balanced Microwave generator supplies a fixed reference wave and that an evaluation circuit provides a measure of the difference between the Frequency of the first and the frequency of the second oscillator provides.

Fin embodiment of the Frfindi-ng will now in the following on Flaue! emer for example !! drawing explained in more detail, where

Fig. I schematically erne embodiment of the Device and

F ι g 2 shows in section a cavity resonator, which can be used in the device according to P ι g 1

In F- i ». 1 you can see the device that one

-. ... Ii r .... _. ι: ..... / · ΐ ".. II..UI"

contains reson.itor, the quality factor of which is relatively low (e.g. - 20). This generator injects scm output signals! into a circulator C1 whose entrances are numbered from I to 4 Please note. that a circulator transmits a ι rhallrni wave from one of its allotment to the next access and this in a pleasant cooling (here in Rkhluni! .ius / u passage 2 exits, du · Wi-IIi- du · is fed in via port 2, from Zug.inr λ .lusirili etc. The I ic quency of the wave emanating from the generator <> I is. as further below still 'Tschriehen is determined by the WeIL- the / um ZtiiMn ·. · * of the circulator (I arrives The wave originating from the generator for I, which emerges from the inlet I of the circulator? CI, controls a second generator Ci 2 with a larger 1 performance as the first to market the services

^{Send back} wave / um access 1 read circulator CI. which transmits this to its access 2. This is connected to an insulator / 1, which allows the passage of the well · · only in one direction, here in the direction of the low arrow. The shaft then passes into a directional coupler CD. which divides the toilet into two parts, one of which after having passed through a second circulator C1 . An antenna 1 \ 7 feeds the latter directly to the object or target to be measured (a

κ electromagnetic wave .1. This is reflected and a standing wave forms. whose 1 lequen / on \ bstand .S between the antenna 1 \ 7 and the measuring object (depends. The standing wave caused by reflection at the target C returns to the antenna I V7, enters the circulator '"L at 2 and comes at S leather out to then through a Abschwach;. r a I and a phase shifter D 1 / go u danr> enters it in the access 3 in the circulator CI a come out to the access 4 and to control the generator G I...

The generator (! 1 can be a Gunn diode generator. These diodes are characterized by the fact that they emit current surges as soon as a certain DC voltage applied to them is exceeded (Gunn effecti. Detailed explanations about these diodes can be found in the Publication "Gunn diode. Leil of an iracable radar device" by M. Bichara in the "Annales des" lelecommunications ", vol. 26, No. 1 to January 2 to February 197, linden. The frequency of these electric surges depends on a certain number of parameters, inter alia by the geometrical Abmessun η of Diotle. the concentration of impurities in active leil. l.inkapselung of the diode, etc. it can be arranged that these frequencies constitute a fairly broad range by selecting an appropriate cavity resonator is used as it is described below.

4; The generator C, 2 can contain an IM PATT (IM Pact ionization by Avalanche and Transit Time) diode, its frequency being controlled by the first generator. Instead of this generator G 2 , an amplifier between the access 2

so be attached by CI and / 1. This allows a circulator with only 3 instead of 4 accesses to be used.

The I elements described above form one

ll .. ~ ..- C -..., ί l- ..Il .1, ».->,. ,, - ;, ·, .l, .r AWctitK-l V 7UM-

see the antenna and the target serves as a resonator. To simplify the following calculations, we assume. da '. "- /. B. the frequency H) CiHz emitted by the generator G I and that the distance S M) cm. It follows from this for the! .. iiif / eit

hu antenna aim and back of the electromagnetic wave

, _I , ⁱ 'Il ^cm ?. H) "see 2000 psec.

'10' em sec

h ', where VI () "' em sec is the speed of light. A wave oscillating at IO GHz has a period of KKlpsec. Between the antenna and the target, a stationary wave will arise into which one

during the term 20m; il the period hmcinnrinacn can

2 (XX) pscc
lÖOpscc

■ ')

Because this wave is standing. will increase the number of Do not change periods for small shifts of the target. If you now move this target by 0.3 cm (- I.S) shifts, the I will change to / cn to the seeing wave / u received. from which it follows

U cm

2 <>? <Ipsec

. · »10 '" cm se,
This results in sn.h cmc '\ nderuni: the pen ode 7 2020 pscc

HU pse <.

what a \ rennen / von w. ^ ni CiH / corresponds to the difference I / bc / uglich the original} rcqucn / is aKo w MH /

If the distance .S. '(>. (I ^ cm becomes

i .lilf / Vii

on

'Id' _t

HKI 1

vias cmc; Frequency of Pv) Q (Ki; CiH / cntsprichi Dk difference I 1 is therefore <J. <«MH /

One can also calculate the 1 1 for smaller displacements.

is is hm / u / uiugen. that the frequencies / differen / s I / are independent of the height of the frequencies that are contained in the spectrum of the generator (VI. If this i requcn / is chosen to be small, the period T and the wavelength / are greater: the number π of bulges and the knot of the standing wave also becomes smaller Da «. Ratio

the cir Mat · tin d? c ^ ndeninc the Frequer ..; s ;. will remain constant

On the other hand, sensitivity increases

K KICIiICi ut "i." \: I> tAliu. » in the

The frequency of the oscillator * depends on the frequency spectrum of the generators G I and C> 2 on the distance 5 A time will add to the DC voltage applied to the diode, the frequency of which falls within the spectrum of the generator, and the current impulses are preferentially emitted when the total applied voltage reaches its maximum, whereby synchronization is achieved: wire;

One recognizes; on Fig i. aah the aa «derr. /further. Exit de> directional coupler CD out * οτπτηεη-de wave through an attenuator Al and a phase shifter Dl succeeded !, lim get on one of the inputs of a T-Kup | i! Ung / U. A three generator Gi with a great figure of merit sends one

s wave with a certain frequency through an isolator / 2, an attenuator A3 and a phase shifter D 3 to / because the input to the coupling T, the output of this coupling, which is generally called "magic Τ", kst'im ukilil weise the vcktoriclle

ίο addition or subtraction of incoming waves. The resulting wave then passes through a demodulator Dl. M and d ^ nn through a low-pass filter / ¹ Zi. a DC amplifier 4MP. a limiter / IM. before there f reqjcn / out

is the demodulator /) / ■. Vf is converted into a measurable electrical signal in a frequency-voltage converter COV . This electrical signal can be converted into a hcrkomnilu n -.- n Mcßgcra! W £ 5 can be evaluated in the vicinity of antenna 4 \ 7 be! su-h emc I mse / .. order from the antenna Auscslrahi.v Λ hurry to focus on the object to be measured. Eliminate any sore waves that are not reflect at the focal point of Mcßucllc! graze

2S Returning to the values of the previous example, let the generator O3 cmc wave m.t send out an exactly «.η frequency of 10GHz, whereby dci output ues ι ^ modulators /> M / a Signal, whose! rcqucnp dci difference between the Rcfcren / ficqucn /. which corresponds to a given distance .S, and corresponds to the frequency of the sensor (.1 for an arbitrary distance S , i.e. it becomes the image of the change in distance S. where this change in the measuring instrument VjfJ.S

t < can be evaluated

The F ι ε Γ shows in Vhmii a possible A> is guiding example of a cavity resonator * · R / u together with one (iimn Dt <> dc. Which forms a Hvperfre <4uen / -Generatoi The resonator consists:

from a vlindrisiht-n ι ichausc I from gu: conductive metal, like / B Kupier «read with a cbenf.'lis made of copper IXikcl 2 is closed with the whole case ribs cr;: hal! to improve the cooling of the device / u Fm solid copper cylinder 3 occupies the center of the resonator and is screwed onto a Flektrode 4, which is part of a Coaxial steekcrs is. which consists of an insulating part 5 and a wide flex electrode 6 see! The 7 \ Ιιγκ .. · τ 3 rests directly on a device, soft the Gunn-

<= o Diode Dd contains, which is / between two contact plates 7 and 8 These two plates are used to adjust the Absfandcs / between the cylinder 3 and the housing 1 and to adjust the diode in relation to this distance The quality factor Q of a rö söfchcfi vVcficiduns slope! inter alia from da Oberfiachenquahtai of the. Resonator forming part ah This Resonatorivp is called coaxial and re-entering

For night work the device according to

Fell the phase shifter DI not lsi absolutely necessary in order for the reflected wave geesgriete Phasenbedmeungcn / u get one can adjust the predetermined distance S For a manufactured on an industrial scale device can dCT attenuator 4 2 are omitted because the \ x hälinis of services between the W ^; elk from the generator G 3 and that of the oscillator by means of a suitable arrangement of the directional coupler CD.

can be fitted. The same applies to the attenuator A 3 and to one of the two phase shifters D 2 or D 3.

The device thus makes it possible, after the zero setting with the help of the attenuators AX, A1, A3 and the phase shifters DX, .02 and D3, to determine the extent to which any object or target deviates from a predetermined position, and this with the help of an oscillator, its frequency

is a picture of the distance between the antenna and the target. This instantaneous position measurement can easily be converted into a dynamic measurement in the event that the target C vibrates. In this case, the demodulator DEM will send out a frequency-modulated signal, from which both the vibration amplitude and the absolute value of the position of the target can be determined in a manner known per se.

1 sheet of drawings

Claims (17)

Claims 1. Measuring method for determining the relative position of an object, characterized overall ^s denotes that the distance between an antenna and a target is used as a resonator of a hyper-frequency oscillator whose frequency with a reference frequency of said oscillator for a given ' ° Distance antenna target is compared, the result of the comparison being a measure of the difference between the valley distance antenna target and the specified distance. 2. The method according to claim 1, characterized in that the comparison of said Frequencies happens through a combination of the two waves, with the difference between is determined at both frequencies. λ. Method according to claim 1, characterized in that that the wave reflected from the target for controlling the frequency of said oscillator is used. 4. Apparatus for performing the method according to claim 1, characterized marked- * 5 net. that a first hyperfrequency oscillator with at least one broadband microwave generator, an antenna and a feedback circuit delivers a wave whose frequency is from Absland Anteni ... goal depends on that a second Hyperfrequency oscillator with a narrowbandigeii IvlikroweüeTi-Gcncra'.or es,. · Fixed Reference wave delivers and da3 ei.-; Evaluation circuit a measure of the difference / wipe the Frequency of the first and the frequency of the second oscillator provides. 5. Device according to claim 4, characterized in that that the first oscillator includes a first circulator which is generated by the generator Wave transmitted with the low quality factor via a second circulator to the antenna deflects, the second circulator also receiving the Weüc reflected by the disc it via a feedback circuit and via said first circulator to the generator the low figure of merit. 6. Device according to claims 4 and 5. characterized in that said broadband generator includes a Gunn diode mounted in a cavity resonator. 7. Device according to claim 4, characterized in that that the / wide oscillator also contains a Gunn diode generator. 8. The device according to claim 4, characterized by a directional coupler, the from Generator with the low figure of merit sentc divides the wave into two parts, with one part for the measurement, the; iniicre Tci! for comparison with the return is determined. 9. The device according to claim 4. characterized gc- »o indicates that the first () oscillator has a second Has generator with an avalanche diode is designed Device according to Claim 4, characterized in that the first oscillator contains an f> a amplifier. 11. Device according to claims 4 and S, thereby uekcnn / eichnei. that the measuring shaft and unite the reference wave mcIi in a "magic T". 12. Device according to claims 4 and II. characterized in that this association cmc is vectorial addition 13. Device according to claims 4 and 11, characterized. d: eat this union cmc is square subtraction. 14. The device according to claim 4. diidiir -.- h iiemarket. that dis- Ausvvertungsschah, nu contains a demodulator followed by a circuit that allows the frequency of the from this demodulator sent signal to reevaluate. 15. Device according to claim 4, characterized in that that the feedback circuit of the first oscillator is one of a phase shifter • contains refoliiten attenuators. 1 (y device according to claim 4, characterized in that it contains a phase shifter around an attenuator, the measuring wave passing through it before it is combined with the reference wave. 17. The device according to claim 4, characterized in that the second oscillator has a attenuator followed by a phase shifter.